This invention relates generally to well tubing anchors, and more particularly concerns an anchor and its method of use which overcome many problems characteristic of known anchors.
Two types of tubing anchors are commonly in use today. One has a slip-cone wedging engagement with well casing that provides the stability in the casing. This type requires tubing rotation to set it and accurate well data to make calculations so that the correct amount of tension can be pulled into the tubing. In order to land the tubing in tension, a special threaded tensioning device is required at the top of the tubing. Also, to release the anchor, the tubing must be rotated to the right. Experience shows that such anchors are sometimes very difficult to loosen from the casing.
The other type of anchor is an hydraulic tool utilizing a piston that pushes a shoe radially outwardly against the casing. While this type anchor sets automatically without any tubing manipulation, it does not provide the stability in the casing that the slip-cone type anchor provides. For example, it often undergoes a slight movement that causes the seal or packer to fail in heavy pumping wells. Also, this type anchor sets prior to tubing elongation that tends to buckle the tubing above the anchor.